The invention relates to cutting devices and more specifically to a compact pneumatically operated device for forcing a cutting die into engagement with a workpiece of flexible material to effect cutting thereof.
Apparatus for cutting three-dimensionally shaped workpieces employing one or more air inflatable bladders to move a workpiece into engagement with a cutting or shaping die are known as disclosed, for example, in U.S. Pat. Nos. 4,420,958 and 5,299,482. These devices and others, of which applicant is aware, are fairly massive and employ air inflatable bladders of the continuous or balloon-type. Such bladders substantially increase the overall size of the device and are susceptible to breakdown when repeatedly flexed in the side areas where the upper and lower sections thereof meet. Applicant's device in contrast employs a single sheet of air impervious material which is secured in airtight engagement around the peripheral edge thereof to the base. The base forces a platen positioned thereon toward a fixed, spaced apart plate upon the introduction of pressurized air beneath the sheet material.
In order to contain the great pressures generated yet keep the device of a size suitable for table top use, applicant employs C-shaped frame members for mounting the various support plates which results in an unobstructed area that enables the sheet material workpiece to be moved horizontally in a straight line direction or rotated beneath the cutting die.
In addition, because great pressures can be generated between the plates by expansion of the sheet material upon introduction of pressurized air, serious injury to a person's extremities can be caused. Thus, applicant employs controls located on the top of the device having spaced-apart valve control knobs, each of which must be depressed by a hand of the user thereby insuring the hands or fingers thereof cannot be between the plates.
It is therefore the primary object of the present invention to provide a superior, user safe pneumatically operative apparatus for cutting leather material and the like.
It is another object to provide a cutting device of the subject type which employs a bladder consisting of a single sheet of air impervious material to ensure long operating life.
It is yet another object to provide a cutting device of the subject type which is very compact and versatile due to its use of C-shaped frame members.
It is a further object to provide a cutting device of the subject type having controls located to ensure user safe operation.
It is still further object to provide a cutting device of the subject type that is relatively inexpensive to manufacture due to its few moving parts yet is economical to use and maintain and is highly reliable in its operation.
These and other objects and purposes of this invention will be understood by those acquainted with the design and construction of cutting devices upon reading the following specification and accompanying drawings.